Many flexible packaging containers have been developed for food products which are consumed over an extended period of time. It is important that the package be tightly re-closed to keep the remaining contents fresh for several days or weeks after the first opening of the package. Furthermore, the cost of the package must be kept low.
In some instances, the package is provided within a stiffer protective carton. In other cases it is a heavier gauge plastic material sufficiently strong to protect the contents without an outer carton.
Typical of this type of package is the glassine or waxpaper or plastic film material which is used in marketing dry breakfast food cereals such as corn flakes or potato chips, or the like. Another typical food product is a small block of cheese sold in a clear plastic film.
In each of these products, the user opens the package, removes a portion of the contents, and then re-closes the package until used at a future time.
Although the products, when initially sold, are fresh and maintained so because of the effective nature of the package, once the package is opened the contents are subject to deterioration, spoilage or contamination.
Merely folding the flexible package is generally not sufficient because of the "memory" of the material and its tendency to open by itself when on storage shelves or in refrigerator.
Many consumers have resorted to using Scotch-Tape or a rubber band to hold the folded portion in place, but it is generally inconvenient because such devices are not always at hand.
In another consumer product, tape-tabs are used to fasten a disposable baby diaper around the infant. These tape-tabs are multi-part devices, which are applied to the movable end of the product, so that such movable end may be secured in place on another portion of the diaper. In one sense, the baby diaper can be considered a "package" to contain the baby. Prior practice had been the use of safety pins or other non- associated closing devices, but in the more recent past the tape-tabs have been developed with a "reclosable" or "re- fastenable" feature that permits the diaper to be opened, the baby to be examined, and the diaper to be closed several times.
In such a "package" the size of the contents (i.e., the baby) does not change from time to time as the "package" is opened or closed.
An early "tape-tab" closure for non-flexible packaging was disclosed in the Hamaguchi U.S. Pat. No. 3,616,114 which was granted in 1971. This closure was used to fasten the stiff ends of a cardboard carton in "butting" relationship, and was attached to the movable end of the container.
In 1971, Gellert U.S. Pat. No. 3,620,217 disclosed a similar fastening for disposable baby diapers, with a further improvement disclosed in his U.S. Pat. No. 3,646,937 issued in 1972.
The baby diaper market was rapidly expanding in the early 1970's, and Buell, in his U.S. Pat. No. 3,848,594, granted in 1974, showed how a "Y-form" configuration of this tape-tab would provide a further improvement in the closing of a baby diaper product.
The re-closing of flexible packages or bags was considered as early as 1967 and disclosed in Perino U.S. Pat. No. 3,301,466 and with subsequent improvement such as that shown in Jaeger U.S. Pat. No. 4,328,895.
One of the earliest package-sealing devices was shown in Newman U.S. Pat. No. 2,153,310 on Apr. 4, 1939; but, like all the others, the closure device was either secured to the movable end of the package or was intended to be fully removed therefrom during the re-sealing and re-closing process and re-applied similar to the application of a strip of Scotch-Tape.
During the later part of the 1970's and early part of the 1980's, the re-sealability in multiple-closures of many of these products became a critical commercial matter, and one of the improvements is disclosed in the Cronkrite U.S. Pat. No. 4,299,223 which issued on Nov. 10, 1981. The Cronkrite patent is owned by the assignee of this patent. It particularly discloses how a tape-tab with a portion thereof having multiple strips of adhesive can be designed to provide a closure member which is strong in shear but weak in peel strength. However, the Cronkrite patent does not disclose the operative jaw-construction of the present invention.